Quad 306 Power Amplifier

Quad 306 Power Amplifier

Quad 306 Power Amplifier

The Quad 306 was a highly underrated solid state amplifier introduced by Quad primarily to power the Quad 10L bookshelf loudspeakers which at the time were Quad's only dymamic loudspeakers on sale and also their first as well, although strictly speaking they were an Spendor OEM design rebadged by Quad.

First launched in 1987, the Quad 306 Power Amplifier was a 50 watts per channel rated amplifier that basically resembled a Quad 405 sliced in half. The Quad 306 was a very solid amplifier that was beautifully built, although minimilist in looks very much followed the design looks of older Quad amplifiers. Unlike the Quad 405 which has a huge power supply under it's bonnet, the Quad 306 Power Amplifier used a large torridial transformer which although very poweful was only a couple of inches in height meaning the designers at Quad could build an amplifier that was much slimmer nad more compact than any of its predecessors.

The Quad 306 Power Amplifier won praise from many camps as being more than a capable perfomer and although primarily designed for the Quad 10L loudspeaker and not any of the Quad electrostatic range, many Quad owners did indeed partner the Quad 306 Power Amplifier with electrostatic loudspeakers and with success although the bigger more powerful Quad 606 Power Amplifier was the ideal and optimised choice for the electrostatic loudspeakers at the time.

The Quad 306 Power Amplifier was in production until 1997 before being withdrawn after nearly 25,000 units being sold. Like all Quad amplifiers, the Quad 306 Power Amplifier was built to last and a large proportion of that 25,000 are still in service today and regularly change hands on ebay.

Not the best Quad amplifier ever made and not as popular with enthusiasts as the Quad 303 or the Quad 405, it is still a very good amplifier.

Quad 306 Power Amplifier Specification
Power Output: 50 Watts per channel into 8 ohms
Distortion: < 0.003%
Hum and noise: -105dB
Input connectors: RCA phono sockets
Input Sensitivity: 0.375v
Speaker Terminals: 4mm banana plug sockets
Voltage: 220-240 V (UK)
Overload Protection : Yes (Resettable via push button at the back of the amplifier)
Additional Mains Output : YES (IEC socket)

This entry was posted on Thursday December 28th, 2006 at 4:40 PM and is filed under Amplifiers. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response.

18 Responses to Quad 306 Power Amplifier

Russell Says:
May 3rd, 2007 at 9:24 PM

The Quad 306 was designed with the Quad ESL63 in mind, Quad's only speaker at the time, long before the 10L speakers were introduced. In fact, in their brochure Quad recommended the 306 for "the vast majority of domestic systems", adding that the 606 "provides enough power for the largest and most demanding systems". They say "the Quad 306 and 606 use identical circuit designs and the only difference between them is their power output." In 1994 the Quad 306 retailed at £350 inc VAT, the 606 at £690.

John Says:
May 5th, 2008 at 10:28 PM

Russell's spot on with this one. I bought it to power our 63's at the time- the 10L didn't exist yet. Now I use it to drive our 988's. Installed the dada electronic modifications (new op amp, capacitors, and output connectors). Sounds great.

Pretty sure the 606 would have put the 63's in the arcing and sparking mode.

Paul auclair Says:
September 16th, 2008 at 2:33 PM

I have a 306 power amplifier and a control unit 34. I intend to sell both units, Do you have any idea how much I coudl get for these 2 units. In perfect condition.

Thank you in advance

Paul Auclair

Hi-fi-insight Says:
September 16th, 2008 at 2:40 PM

A good condition Quad 306 and Quad 34 should normally sell for around £150-200 each on Ebay.

Da bishop Says:
September 23rd, 2008 at 8:59 PM

all of the transistor gear that quad made was never hyped or advertised particularly hard, especially in the US. Most of it was built for the BBC and recording studios, so it's pro gear. Quad is not really a consumer brand, it's a pro and enthusiast brand, so there's a healthy community of modders and service people. Great stuff to own.

Leigh Says:
March 17th, 2009 at 7:22 PM

Does anyone know if a pair of 306 quads could be used in a monobloc configuration? If so, what config changes would I need to make to the 306s?

Jules Says:
May 19th, 2009 at 3:52 PM

yes, Fidele Audio ( http://www.fidele.co.uk/ ) in Scotland will do this for around £20.

Jonathan Says:
November 15th, 2009 at 10:58 AM

Thinking of buying a second 306 - could these be run in bridged mode?

Peter hickman Says:
November 27th, 2009 at 8:54 AM

Hi, the 306 (and 606) can be configured in either current or voltage bridging, depending on what is needed. Current briding is good for really difficult loads, voltage bridging gives more power. But the best configuration for quality is bi-amping.

Patrick Says:
December 6th, 2009 at 2:59 PM

I have two 306s. I have them bi-amped to two KEF Q65 floorstanding speakers and use a Quad 44 pre-amp. I have been thinking of "upgrading" to two Quad 606s. I love the sound but as I am sure is the case with some (all) of you, I am always tinkering. What do you think?

Jaybe Says:
February 4th, 2010 at 7:38 PM

Hi, I have inherited a Quad 34/306/FM-4 system and I am currently looking for speakers to match it. I am giving a lot of thought to the Arcaydis DM-1 units as they have been reviewed favourably as being particularly "musical". These speakers are only available 'on-line' so a subjective appraisal isn't possible. I favour classical music. Would I be doing the right thing in purchasing these; would they 'match' the 306 system?

Andrã© Says:
August 24th, 2010 at 8:02 AM

Hi all, I just bought an original 405 which will be upgraded to a 405-2 and considering buying also a 306 and than put the bass/treble filter (which is now inside my speakers) in front of the 405/306 combination so that the 306 drives the treble and the 405 the base part, so the whole system becomes like an active loudspeaker system. Anybody out there who has done/tried the same??? Or can somebody tell me whether or not this is a good or bad idea? Thanks!

Carlos Says:
September 27th, 2010 at 10:54 PM

I'm thinking about changing my quad 405 for a 306 is it a good idea does it have a better sound?

Martin Says:
May 28th, 2011 at 2:44 PM

I have owned a Quad 34/306 for many years, I've never been able to fault it, the only other equipment it hasn't been able to outlast or perform, is a Goldring Lenco GL75/Ortofon VMS 20E MkII. Superb phono stage. All that guff spouted of about jocky wheeled turntables in the 1970's ?? British electronics and Swiss enginerring, perfect.

Joy Says:
January 3rd, 2013 at 12:19 AM

I purchased a second-hand Quad 306 on ebay, and now match it with my beloved Harbeth C7s. The combination sounds superb! Give it a try!

Rupert Says:
January 4th, 2013 at 3:51 PM

Have been using Quad amps for years. So I'm not very familiar with other sounds but I really haven't had much incentive to do so. I stream music with a Airport Express into a D2 Maverick DAC (optical port) to a Quad 34/306 and into a pair of KEF LS50's. I am currently consideringa Naim or Linn all-in-one platform. Has anyone got any comparative experience with Quad / Naim / Linn / Kef ? Thank's

Joaquim Says:
April 14th, 2013 at 9:19 PM

Dear John

You said "Installed the dada electronic modifications (new op amp, capacitors, and output connectors). Sounds great."

Can you tell me whath are specifically those mods? I'm interested to do it in my 306. What were the sound benefits ?
Thank you


Mark harris Says:
July 5th, 2013 at 1:03 AM

Just vertically bi- amped my 306's with a cambridge c70 control amp . What an incredible difference over using a solo 306..... wow

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